Suppression of Stress-Induced Defects in FinFET by Implantation and STI Co-Optimization

Defects originated from the stress-induced fin dislocation in FinFET have become critical in taller and narrower fin structures at advanced technology nodes that can easily form a leakage path between the source and the drain, leading to direct short failure. In this work, the correlation between the stress-induced defect and device leakage current has been studied using 14-nm FinFET devices with different fin structures. A novel method to detect and quantify the fin dislocation defect has been developed by characterizing the leakage performance, which can be used to evaluate the process effects. The asymmetric stress from shallow trench isolation (STI) oxide film and fin damage by ion implantation are verified as the primary causes through statistical analysis, which have been further co-optimized to achieve a higher yield.